Complicate truncate behavior.
diff --git a/coreutils/dd.c b/coreutils/dd.c
index a0d2330..32eeb66 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -41,7 +41,7 @@
int dd_main(int argc, char **argv)
{
- int i, ifd, ofd, sync = FALSE, trunc = TRUE;
+ int i, ifd, ofd, oflag, sync = FALSE, trunc = TRUE;
size_t in_full = 0, in_part = 0, out_full = 0, out_part = 0;
size_t bs = 512, count = -1;
ssize_t n;
@@ -94,8 +94,19 @@
}
if (outfile != NULL) {
- if ((ofd = open(outfile, O_WRONLY | O_CREAT, 0666)) < 0)
+ oflag = O_WRONLY | O_CREAT;
+
+ if (!seek && trunc)
+ oflag |= O_TRUNC;
+
+ if ((ofd = open(outfile, oflag, 0666)) < 0)
perror_msg_and_die("%s", outfile);
+
+ if (seek && trunc) {
+ if (ftruncate(ofd, seek * bs) < 0)
+ perror_msg_and_die("%s", outfile);
+ }
+
statusfp = stdout;
} else {
ofd = STDOUT_FILENO;
@@ -113,11 +124,6 @@
perror_msg_and_die("%s", outfile);
}
- if (trunc) {
- if (ftruncate(ofd, seek * bs) < 0)
- perror_msg_and_die("%s", outfile);
- }
-
while (in_full + in_part != count) {
n = safe_read(ifd, buf, bs);
if (n < 0)